This invention relates to a device which prevents separation of a doorjamb and door to provide security against forced entry into a building.
The entrance to many apartments, office buildings, schools and other buildings are made of metal doors and door frames which are subject to forced entry by an intruder. Such entranceways are typically arranged so that the door is locked from the outside yet it allows easy exit from the inside. A typical lock set may comprise a latch lock which allows a person exiting the building to pull down on a handle to open the door. The door remains locked from the outside when it is in the closed position.
Despite the fact that the door is closed and locked from the outside, an intruder may still force his way into the building by using a crowbar or other leveraging device to force the door open. The latch on the lock set extends from the edge of the door only about 1/2" or so, and, when the door is in the closed position, the latch protrudes into a recess in the doorjamb. By inserting a crowbar between the edge of the door and the doorjamb, the intruder may pry them apart far enough so as to separate the latch on the door from the recess in the doorjamb, thus allowing the door to open.
Others have tried placing a metal cover plate on the door over the area where the latch extends into the recess of the doorjamb. Such cover plates are helpful in preventing the intruder from tampering directly with the lock, but the intruder may still pry apart a door and doorjamb far enough so as to separate the latch from the recess in the doorjamb to open the door.